DIY: FSU (aka Blower Motor Resistor) replacement pictorial guide

Resurrecting this old thread just to say a big thank you. The blower just died, no fuses blown..I thought I could hear it turning slowly so I followed the instructions here to replace the fsu and yay it all works now. I can't begin to imagine how much this website has saved me over the years.

Thanks for the post.

This made the job easy.

Sorry for bringing up an old thread..

I'm new to BMW's and glad there's a helpful community like bimmerfest. Along with someone that know's how to write a DIY.

Originally Posted by Starless

Haha, I just like to take pictures of my repairs when they come up

Thanks everybody for comments. I'll need to include some other good FSU links for those who decide to remove the air duct. It's a couple of extra steps from what I've read.

Starless,

Thanks for the innformation on the FSU. I had the ssame thing happen to me with my CFO in the car on the way to the airport!

I'm also from St. Louis. Do you have an indie place that you use for serious repairs? Dealer is way expensive!

Originally Posted by bobbiejohn

Starless,

Thanks for the innformation on the FSU. I had the ssame thing happen to me with my CFO in the car on the way to the airport!

I'm also from St. Louis. Do you have an indie place that you use for serious repairs? Dealer is way expensive!

Bavarian is an awesome indie shop. Reasonable rates, honest knowledgeable mechanics. Can be opinionated about certain things and stubborn, but I have yet to see a mechanic who would not be... They have 2 locations now, in Olivette and in Manchester. Highly recommend them. They have a very good reputation in stl.

Agree about Bavarian. Very good and opinionated, they do good work for a lot less. Debating on them or me doing the FSU.

Easy fix because of your post.

Thanks Mike

This was my first DIY, whish I had seen this post prior, nice job!!

Thanks to this and a couple other video's it took me 17 minutes to replace the FSU, saved me $200 easy!

Almost longer to watch the DIY's than it is to actually replace.

/hugs!

I had my blower changing and jumping speed for more than a year. This morning it was completely dead. I am pretty sure is the FSU but I'll check the fuse first, it's easy enough.
Thanks for the nice DIY I am sure I'll use it very soon

Currently attempting FSU removal. Ain't budging.

What do you grab to pull it out? I'm grabbing the harness, which doesn't seem too smart and the connector keeps disconnecting when I do and then there's nothing to grab to pull it out.

I did one of these in another E46 a year ago but am just having an absolute hell of a time with this one. Hands shredded from the sharp plastic bits down there.

What am I missing? I'm aware of the locking tab on the FSU and the upper T20.

Suggestions?

Originally Posted by Mark in TX

Currently attempting FSU removal. Ain't budging.

What do you grab to pull it out? I'm grabbing the harness, which doesn't seem too smart and the connector keeps disconnecting when I do and then there's nothing to grab to pull it out.

I did one of these in another E46 a year ago but am just having an absolute hell of a time with this one. Hands shredded from the sharp plastic bits down there.

What am I missing? I'm aware of the locking tab on the FSU and the upper T20.

Suggestions?

Have no idea...It should come out. But let us know when you figure out...I just pulled it by the harness and it came out with zero drama as far as I remember...

Originally Posted by Starless

Have no idea...It should come out. But let us know when you figure out...I just pulled it by the harness and it came out with zero drama as far as I remember...

I just changed my FSU, Great write up Starless. I have a response to the above question. On one side of the FSU is a hard black plastic tab on the side toward the firewall that helps hold the FSU in place. I had to push back and hold it with a screw driver while I pulled and wiggled the FSU out of its socket with the other hand.

Thanks again Starless. I could not have changed the FSU without your write up and pictures.

A few thoughts as a follow-up to my post above.

Although I had done this job once before on another E46, this one really kicked my ass. As I suspected, the original FSU was just an incredibly tight fit. Finally got it out and got everything back together. I'll add to the OP's original write-up that if you have hands wearing anything larger than a medium glove size, get someone with smaller hands to help you. Also, wear work gloves; there's a lot of sharp-edged plastic down there. And of course a small flashlight is key. Mine broke in the midst of the job but I borrowed a nice one to finish up. If you can lodge it up near where you're working, it'll help tremendously. You definitely need both hands free.

It's a hassle mainly due to the contortionist act one has to perform but the job is straight forward and I'd recommend DIY vs paying someone else. Another plus is you can take your time putting it back together, which a mechanic on the clock may not do as carefully as you.

Also, on the topic discussed earlier in the thread about various FSU re-designs:

The first one I replaced came out of an '02 E46 sedan and was the earlier design with a small number of cooling fins. That car had been experiencing the pulsating blower fan symptom. This recent one I removed from a June '03 E46 sedan and has the same number of cooling fins as the new Behr FSU. See photos. The Behr part number, however, is different on the 2 units. The original FSU started acting up in summer of 2010. I did not use the car at all during summer of 2011 but I figured I'd replace this year before it went haywire again. I had experienced the fun symptom where the fan won't turn off at all and will kill the battery unless you start pulling fuses (which does work as a temporary fix).

This is a great forum for BMW owners. Especially for those who can do some repairs themselves. I used the instructions as given here to get access to FSU and the instructions are great with pictures. I tried to replace my FSU and got stuck at the control motor. I have removed both T-20 screws holding the control motor and the motor is loose, however, it would not come off from the side slot in the frame. I have tried every way to get it off but have been unsuccessful in my efforts. Is there any special way to tilt the motor in order to remove it? I am afraid that if I use too much force I might break the side tab and end up with a bigger problem. Any helpful tip will be highly appreciated. Thanks.

Indru

As noted in prior posts, you do have to move the locking tab toward the front of the car to release it. You don't have to move it much -- the remaining issue may well be what I reported above, that being just a really tight fit. Ironically, the new FSU will pop right in.

It helps tremendously to lodge a small flashlight up near where your hands are working. I lodged it somewhere above the black plastic air vent.

Mechanic's gloves (at least on the right hand) plus a pad for your knees are a plus too.

Aside from all the bending forward, reassembly is easy but do take the time to think thru the correct routing of the wires for the glove box lamp and flashlight charger.

I just replaced mine the night before last. The blower had been acting up off and on for the past year. It had worked flawlessly for the past few months and then the day before yesterday it quit. It was 105 degrees that day! So, I came back to this DIY and printed it out to take to the garage! The hardest part for me with this DIY was getting to the 2 Torx screws, especially putting them back in!!! I taped the screws to the end of my Torx Driver when reassembling. I just don't see how you can successfully get them back in without doing that or having a good magnetic Torx driver! Anyway, much appreciated Starless!!!

Thank you so much from the deep of my heart and wallet!!
I replace the fsr in my 2001 330i following your diy.
I pay 23$ for a new resistor in Ebay and i did the job in 1 hour.
I really appreciate you.

You are very welcome and welcome to the forum!
Make a thread if you need help in the future with anything else, there are people here who can offer a solid piece of advice.

I appreciate all of you for posting here - I have no doubt i would have paid hundreds of dollars for this fix at the dealer or somewhere else..

I paid $52.09 at www.autohausaz.com - and they shipped it to me for free. It took me 15 minutes to put in, most of which was trying to get it to fit back in (it did not, fully - although the bolt holes lined up, it wouldnt go in far enough to click in. But it sat firmly in the spot).

Im thanking God for you guys right now! No more riding in the rain with the windows down.

Originally Posted by Bimero

Thank you so much from the deep of my heart and wallet!!
I replace the fsr in my 2001 330i following your diy.
I pay 23$ for a new resistor in Ebay and i did the job in 1 hour.
I really appreciate you.

You probably bought a cheap sub-par in quality FSU that comes from China.
These frequently fail quickly. Don't be surprised.

I'm convinced that this is a problem with electrical contacts and not a part failure. Anyone else?

Just a quick Thank You to Alex for doing this write up . I'm not sure what the dealer charges for this repair but I'm sure it's more then the $60 I paid for the part.

The blower in my wife's 2001 330 died two weeks ago so I started searching for a fix and found your thread. I read your instructions and after 45 minutes kneeling on the garage floor reaching under the dash I had the FSU replaced and everything back together again. The blower woks as it should and my wife is happy so that's all the matters .

As for the FSU itself.... Mine is the BEHR/Hella one pictured above and I order mine from AutohausAZ for $60 shipped.

Anyway, just wanted to say Thank You for saving me and many others a trip to the repair shop.

Gerry

Great DIY, thanks for that.
Once I completed the FSU install I noticed that I had broken the plastic connector on the control motor to the metal rod. I tried to figure out what it does, when I turn the AC off and on it actuates 180 degrees, but I see no change in the functionality of my AC.

A few questions for you guys:
1. What does this part actually do?
2. If I can live without it, should I zip tie the rod one direction or the other?
3. If I can't live without it, does anyone know how to replace it? Half the plastic is still attached to the rod and my searches online haven't revealed the exact piece of this part that I need, nor how to disassemble the big part that I have (pic below).

Thanks again!

My understanding is that this motor is responsible for switching between supplying the flow of air from the outside and re-circulating air withing the cabin. Activated by the corresponding buttons below the HVAC controls. You can live without it but if there is a diesel truck in front of you, re-circulation usually helps :-) Not sure how to go about fixing it, I'd somehow figure that out if I needed to, but I've never done it before.